This invention relates generally to the field of rapid prototyping and more specifically to a machine for precisely delivering and affixing solid media for the purpose of creating prototypes of varying size and precision.
There has always been a need to model inventions, machines or structures to allow people the ability to visualize their design in three dimensions that was just flat on paper or sketched. Modeling and machining of these visions became time consuming and greatly added to time it took to create a product and deliver it to the marketplace. With the invention of computer aided drawing and eventually 3-D modeling, people could see their design on the computer screen in 3-D. To get from this design point to a physical prototype still took machining and modelers and more importantly time.
With the advent of computer controlled printing using liquid inks sprayed or bubbled onto a paper came the notion that the same device could be used to “print” 3-D objects. Several methods were developed to create 3-D objects from powder, liquid or hot plastic. All the devices used a build platform that could be raised or lowered as each layer of the object designed in CAD (Computer Aided Drawing) was hardened or glued. Multiple layers then were added and the 3-D object would appear in the liquid, powder or on the build platform. These objects could then, on a small scale be used to test color, fit and design characteristics. The prototypes are relatively cheap and can be produced quite fast but are extremely limited in size. Thus the rapid prototyping industry emerged.
In contrast, however, the auto industry and aircraft industry would build prototypes of wood or clay. These large scale models could then be used to test in wind tunnels or admired and scrutinized by designers and the firm's decision makers. This process is extremely time consuming and costly.
The method of computer printing using liquid inks sprayed or bubbled onto a paper was amended to a new process that would “print” 3-D objects using an adhesive bubbled onto a build platform covered in powder. The adhesive would glue the powder together in the precise shape described in a 3-D CAD drawing. The build platform could then be dropped down to allow the next microscopic layer to be “printed.” In this manner, layer after layer of adhered powder could be laid down to eventually create, on a small scale, a 3-d solid object “print” made up of layers of glued powder. Excess powder would then be removed and the 3-D object would be apparent. This technology is limited to a size of approximately 12″×12″×18″. Objects “printed” could then be used as prototypes to test materials, size, fit, and color without going through the expensive and time consuming process of molding individual pieces, machining or carving.
Further technology involves the use of laser scintering which utilizes a pool of laser activated liquid resin that can be turned to solid by the precise aim of a laser on a submerged build platform. As the laser changes liquid resin to solid, the platform moves to create layers and thus 3-D objects rise from the liquid and are used in the same manner as described above but are less strong and precise.
Another similar technology evolved that bubbled microscopic hot plastic to the build platform. Layer after layer of hot liquid plastic dots was laid down, thus creating the 3-d object. These plastic models are much stronger, and in some cases can be used for pressure testing as well as fit and design testing.
The types of rapid prototypers described above cannot be applied to larger objects such as automobiles or aircraft. Currently, autos are designed on CAD programs and the design is fed into programs controlling large multi-axis CNC milling machines. These machines carve large blocks of foam or clay coated foam to create the shape of the vehicle or aircraft envisioned by the designer. The prototype can then be tested for shape, color, wind resistance and flow much as the above pieces, except on a larger scale. No interior spaces are created in this process, however.
In the three rapid prototyping methods described above, powder adhesion, laser scintering and plastic deposition, there is a major deficiency that all three have in common: size. Size matters, especially in certain industries where large items are created. The aforementioned rapid prototypers are limited to 12″×12″×18″. Sometimes the objects can be glued together to create a larger object but then the new object lacks precision and strength.
In the auto and aircraft industry, large multi-axis machines machine large shapes from foam or clay covered foam. These prototypes are only good for visually inspecting and testing the exterior of the vehicle as the interior of the vehicle cannot be modeled or shaped due to access of the large machine, also lower portions and the underneath of the car is not prototypeable with this method.
The device according to the present invention was expressly designed to solve the prototype size problem. The new device teaches building prototypes by gluing spheres of any diameter from BB size to say basketball size to each other in a carefully computer designed array as to represent a 3-D CAD drawing. The device according to the present invention can build prototypes much larger than the prior art. The preferred embodiment would utilize media balls of a diameter determined by the size of the prototype to be built and the quality of “print” needed. As an example, for smaller prototypes of the size of say a car engine, smaller bb size metal balls might be used to not only “print” the shape, but may be approximate the weight also. The smaller the media, the better the quality of the “print”, much as a ‘dots per inch’ determines the quality of print materials. Furthermore, the device according to the present invention can “print” full size aircraft wings and fuselages that can be used immediately for preliminary wind tunnel and design testing.
Also, prior art is limited in the materials that can be utilized. Cornstarch, resin and plastic utilized by the three prototypers mentioned prior respectively, are the only materials that can be used. The device according to the present invention can utilize plastic, steel, aluminum, brass, composites, resins, clear acrylics, glass etc. Practically any material that can be output into a uniform shape can be used.
With respect to the automotive industry, the device according to the present invention, has significant advantages over prior art. First of all, vehicle prototypers can only cut exterior surfaces. The device according to the present invention can “print” the entire vehicle INSIDE AND OUT. Interior design, underneath the vehicle, engine, transmission, all can be “printed” by the processes of gluing little balls together in a precise manner. The printed prototype itself may be displayed as a promotional piece as it emerges from the prototyper almost as a piece of art. In an equally important embodiment, the device according to the present invention can use a media comprised of cylindrical cut to length pieces that will allow flat surfaces to be “printed without major voids or even cubic media with no voids. The larger the media the quicker the “print” For vehicle prototyping, larger media can be coated and sanded smooth with filler. Finished “printed” parts can be dipped in epoxy for strengthening.
The device according to the present invention, when applied to the aircraft industry prior art of molding with wood and fiberglass, has many very significant advantages. First of all, size. There is no limitation to the size of the prototype. Entire aircraft can be “printed” multiple machines can glue up an aircraft of aluminum or modern composites with all the interior voids and may even have the strength to be actual components.
The device according to the present invention can also change media size so that structural components may be built faster out of larger media while surfaces may need smaller media to be smoother and more precise.
The device according to the present invention saves labor, as the machines can ‘print’ at night and weekends with little supervision.
In a further embodiment, entire buildings and houses can be “printed” out of say, ping pong balls, glued around plumbing and conduit runs, coated with plaster and stucco and occupied immediately. Air space in the ping pong balls would provide insulation and the spherical shape would provide excellent strength.
In conclusion, the device according to the present invention is a vast improvement over present powder, laser scintering and hot plastic prototypers because of the device according to the present invention's ability to “print” prototypes of large size and strength of varying materials. Furthermore, with respect to the automotive industry, the device according to the present invention can “print” interior spaces and entire vehicles including the underneath. Also, the device according to the present invention, with respect to the aircraft industry can create full size aircraft, work at off hours, and print parts that may be structurally useful. Finally, the device according to the present invention, can “print” designs and parts the size and shape like no other prototyper. Entire houses and buildings or large mechanical prototypes are possible with a mixture of media sizes and types.